You have shown me a strange image, and
they are strange prisoners. Like ourselves, I replied; and they see
only their own shadows, or the shadows of one another, which the fire
throws on the opposite wall of the cave? True, he said; how could they
see anything but the shadows if they were never allowed to move their
heads? And of the objects which are being carried in like manner they
would only see the shadows? Yes, he said. And if they were able to
converse with one another, would they not suppose that they were
naming what was actually before them? Very true. And suppose further
that the prison had an echo which came from the other side, would they
not be sure to fancy when one of the passers-by spoke that the voice
which they heard came from the passing shadow? No question, he
replied. To them, I said, the truth would be literally nothing but the
shadows of the images. That is certain.